Airbag apparatuses designed to inflate and deploy an airbag inside a vehicle in the event of a collision, abrupt deceleration, or the like, in order to absorb the impact to be incurred by an occupant are generally mounted in vehicles, such as automobiles. This airbag apparatus generally comprises a gas generator that generates gas under predetermined conditions, an airbag that is connected to the gas generator for inflation and deployment, and a retainer that houses the airbag. The applied shape and structure of the airbag are variegated, depending on conditions such as the installation location and required function.
While the airbag is normally folded up small and housed in the retainer, changes in the direction of deployment and overall shape of the airbag when the airbag inflates and deploys in an emergency greatly differ, depending on the structure and folding method of the airbag itself. In prior art, there have been proposed airbag structures and folding configurations designed based on an object to execute deployment in stages in the direction of protrusion toward the occupant (refer to JP 10-6897 A, for example).
Nevertheless, in the above-described prior art, only deployment in the direction of protrusion toward the occupant was taken into consideration, and not changes in shape with respect to lateral deployment orthogonal to the direction of protrusion. On the other hand, in recent years, there has been a call for the capability to configure changes in deployment shape in various directions to accommodate the layouts of relatively small vehicle interiors.